The present invention relates to novel antibiotics BU-3608, BU-3608B, and BU-3608C having antifungal and antiviral activities and are useful for treating fungal and viral infections in animals and human beings; to a pharmaceutical composition thereof; to a process for production thereof by fermentation of new microorganisms Actinomadura hibisca sp. nov. Strain No. P157-2, ATCC 53557 and Strain No. Q278-4, ATCC 53646; and to the new microoganisms.